Artificial urban glacier to cool Mongolian capital

Mongolia's capital city, Ulan Bator, is planning to keep itself
cool during the hot summer months by shunning air conditioning in
favour of creating an enormous artificial urban glacier.

In a somewhat bonkers plan -- first reported in the Guardian -- the city of Ulan Bator will attempt to
capture some of the cool winter temperatures in huge ice blocks
that will slowly melt over the summer and cool down the city. The aim is to build artificial ice shields
-- or "naleds" --
that occur naturally in far northern climates and can grow to be
more than seven metres thick. They grow when river water pushes
through cracks in the surface of the ice during the day and then
freezes to add an extra layer of ice when night falls.

Engineering consortium EMI-ECOS will try to replicate this process by creating holes in the ice that is forming over the Tuul river.
This will be repeated over and over again until the ice is much
thicker than it would be if left alone.

As the Guardian reports, these "naleds" -- also known
as Aufeis -- have
been used in the past to create river crossings for tanks in North
Korea and drilling platforms in Russia. Climate change is likely to
melt permafrost from most of Central Asia, but some studies --
including this one by geologist Robin Grayson -- suggest that most naleds
will survive and that they could be used to strengthen permafrost,
protect biodiversity from climate change and create "cool parks" to
combat urban heat islands of cities in summer heat-waves.

It is hoped that if the geoengineering trial is successful, the
technique could be used in other northern cities to save on air
conditioning costs.